Polycyclodelfin polymerization process and products

ABSTRACT

Heat curable polycycloolefin compositions comprising (1) a mixture of at least one polycycloolefin having a strained carbocyclic ring, and (2) at least one oxyhalide of molybdenum or tungsten containing at least three atoms of halogen per molecule, which compositions are curable to tough hard products.

United States Patent POLYCYCLODELFIN POLYMERIZATION PROCESS AND PRODUCTS10 Claims, No Drawings U.S. Cl 260/882 D, 260/93.1 Int. Cl C081 15/04,C08f 7/02 Field of Search 260/882 D,

References Cited UNITED STATES PATENTS Epstein et a1. Eleuterio Natta etal. Tazuma....

Crain Primary Examiner-Joseph L. Schofer Assistant Examiner-Richard A.Gaither Att0rneysMartin S. Baer and Norris E. Faringer ABSTRACT: Heatcurable polycycloolefin compositions comprising (l) a mixture of atleast one polycycloolefln having a strained carbocyclic ring, and (2) atleast one oxyhalide of molybdenum or tungsten containing at least threeatoms of halogen per molecule, which compositions are curable to toughhard products.

POLYCYCLODELFIN POLYMERIZATION PROCESS AND PRODUCTS BACKGROUND OF THEINVENTION This invention relates to new heat curable compositionscomprising at least one polycycloolefin having a strained carbocyclicring and an oxyhalide of molybdenum or tungsten at least three atoms ofhalogen per molecule.

It is heretofore known that Group Vlb metal halides polymerizepolycycloolefins, but only slowly, if at all, in the absence of anactivating cocatalyst or solvent such as a Lewis acid or carbontetrachloride or carbon disulfide, and at low temperature.

it has now been found that certain polycycloolefins may be polymerizedand cured in the presence of certain oxyhalides of molybdenum andtungsten to tough, insoluble products having in addition other desirableproperties as will be hereinafter apparent.

The invention relates to a heat curable composition comprising a mixtureof at least one polycycloolefin having a strained carbocyclic ring andan oxyhalide of molybdenum or tungsten containing at least three atomsof halogen per molecule. The compositions according to the invention maybe cured to products which are hard insoluble resinous materials, andmay therefore be advantageously employed in a wide variety ofapplications such as, for example, pottings, castings, laminates,impregnated building materials and the like.

The invention further provides a polymerization process whereby highmolecule weight polycycloolefin polymers are produced in short reactiontime; more particularly, the invention provides an improvedpolymerization process comprising contacting at least onepolycycloolefin with a catalytic amount of an oxyhalide of molybdenum ortungsten containing at least three atoms of halogen per molecule at atemperature in the range between about 20 C. and a higher temperature atwhich the monomer and/or polymer begins to thermally decompose,preferably between about 30 C.'and 175 C.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polycycloolefins employedin the compositions and process of this invention suitable contain atleast one unsubstituted ring double bond. Surprisingly, the oxyhalidesof the present invention are ineffective for polymerizing monocyclicolefins such as cyclopentene and cyclooctene. Polycycloolefinscontaining a strained carbocyclic ring are defined herein as thosehaving a'five-membered or seven-membered carbocyclic ring.

The polycycloolefins contain at least two, preferably from tow to fourrings, which may may be unsubstituted or sub stituted with, e.g., loweralkyl groups, an alkenyl group and the like. Examples of the polycyclicolefins employed in the compositions and process of the invention areendodicyclopentadiene, exodicyclopentadiene, dihydrodicyclopentadiene,norbornene, norbornadiene, lmethyl bicyclo[2,2,l]hept-2-ene, 5,5-dibutylbicyclo[2,2,l] hept-Z-ene, S-methyl, 5-vinyl bicyclo[2,2,l]hept-2-ene,5- isopropenyl bicyclo[2,2,l ]hept-2-ene, I ,7,7-trimethyl bicyclo[3,2,llhept-2-ene, tricyclo[6,l,0 ]undeca-4;9-diene, tetracyclo[6,2, l '0-]dodec-4-ene etc.

Preferably the polymer is a homopolymer of dicyclopentadiene ornorbornene; however, the copolymerization of dicyclopentadiene with notmore than 50 mol percent, preferably not more that 10 mol percent ofpolycycloolefins such as norbornene or norbornadiene is also preferred.The

polymers obtained according to the invention may be thermally cured touseful, tough, hard, insoluble products having utility for laminates,castings, surface coatings, adhesives and the like.

The initiator the for compositions and process according to theinvention is an oxyhalide of molybdenum or tungsten and containing atleast three atoms of halogen per molecule. Thus the catalyst containsmolybdenum or tungsten. Suitable halogens are chlorine, bromine, andfluorine. Examples of LII suitable initiators are molybdenumoxytetrachloride, molybdenum oxytrichloride, molybdenumtrioxyhexachloride (Mo o Cl), molybdenum trioxypentachloride Mo,0,cl,),

molybdenum oxytetrafluoride, tungsten oxytetrabromide, tungstenoxytetrachloride, tungsten oxytetrafluoride and the like. Preferred arethose containing three or four atoms of halogen per atom of metal;oxyhalides having only two halogens such as molybdenum dioxydichloridehave been found to be of substantially lower activity.

The amount of said catalyst to be used may vary within relatively widelimits. Amounts between about 0.0] to about 5 mol percent catalyst aresuitable; amounts between about 0.02 and about 1 mol percent beingpreferred.

The polymerization generally gives rise to polymers containing repeatingunits in which the unit has one ring structure less than the originalmonomer; however, other structures may also be present depending uponthe particular monomers and conditions.

The polymerization is preferably effected with the polycycloolefin inthe liquid phase, and may be effected in the presence of a substantiallyinert solvent such as paraffinic hydrocarbons, e.g., cyclohexane,n-heptane, isooctane and the like. For some applications, thecompositions may contain small amounts, e.g., up to about 30 percent byweight, preferably from about 0.2 to 25 percent by weight of an olefinicreactive diluent such as styrene, divinyl benzene, and the like.However, it is a particular advantage that solvents and diluents may bealtogether absent and the polymerization carried out in bulk. It hasbeen found that moisture adversely influences the reactivity of thecatalyst. The polycycloolefin and liquid diluent, if employed,preferably contain less than parts per million by weight of water andother protonic agents. This may be achieved by such means as azeotropicdistillation, or by treatment with desiccating agents such as calciumhydride. Various additives which are inert throughout the polymerizationcan be incorporated into he monomer mixture. Examples of such additivesare pigments, dyes, fillers, heat stabilizers, antioxidants, ultravioletlight stabilizers, antistatic agents and the like. I

The temperature and pressure to be employed is dependent upon thematerials reacted and the catalyst employed and upon the nature of theproducts desired. The temperature at which the polymerization takesplace will mostly be between about 20 to about 200 C. preferably betweenabout 30 and about C. However, excessive exposure to those highertemperatures should be minimized to avoid decomposition of themonomer(s) and/or polymer. Subatmospheric, atmospheric orsuperatmospheric pressures may be employed.

The catalyst may be added to he polycycloolefin in any convenientmanner; for example, in a powdered or granular form or as a slurry orsuspension in a suitable liquid medium, e.g., hydrocarbon oil. Thecatalyst may be added to the polycycloolefin all at once of continuouslyor intermittently over a certain period of time until the requiredamount is added. Since the reaction is exothermic in many casesregulating the rate of addition of catalyst may be suitable means ofcontrolling or aiding a control of the reaction temperature within thedesired limits. The amount of catalyst used may affect thecharacteristics of the higher molecular weight resin or resinousmaterials formed. Generally it will be necessary to conduct thepolymerization in an inert atmosphere as even brief exposure to anoxygen containing environment such as air adversely influences thereactivity of the catalyst. The compositions according to the inventionare thermosetting compositions suitable for reinforced laminates,castings, surface coatings and the like.

To illustrate the manner in which the invention may be carried out, thefollowing examples are given. Unless otherwise specified, partsdisclosed in the examples are parts by weight.

EXAMPLE I Into an open mold in a dry nitrogen atmosphere was placed 500parts of liquid dicyclopentadiene (DCPD) containing less than 100 partsper million on the polycycloolefm of water at a temperature of 35 C. andtwo parts of molybdenum oxytrichloride. The mixture exhibited a mildexothermic reaction and gelled within 5 minutes. The soft gelled productwas cured one hour at 140 C. resulting in a hard brown resinous producthaving the following properties:

Flexural strength p.s.i. 9,200 Flexural modulus p.s.i. 3.2Xl" Tensilestrength p.s.i. 7,200 Tensile elongation 4.2 Tensile modulus p.s.i. 3.0Xl 0* Hardness (Shore C) 95 lzod Impact Strength 0.78 Dielectric constant2.4 Dissipation factor 0.007 Volume resistivity l0ohm EXAMPLE ll Into aglass reaction vessel from which the air had been displaced with drynitrogen were added ml. of norbornene at 60 C. and 0.04 g. of molybdenumoxytrichloride and the mixture gently agitated. A gelatinous polymerformed within about a minute.

EXAMPLE "I Into a glass reaction vessel from which the air had beendisplaced with dry nitrogen were added 5 ml. of DCPD at 60 C. and 0.05g. of molybdenum oxytrichloride and the mixture gently agitated byshaking the vessel. A gelatinous polymer formed with a few minutes. Theprocedure was repeated with an initiator outside the scope of theinvention, molybdenum dioxydichloride. No gel was observed in 2 hours.

EXAMPLE IV The procedure of example III is repeated with additionalinitiators outside the scope of the invention. Vanadium oxytrichlorideor chromium oxychloride show no or only a slight tendency to polymerize.

EXAMPLE V In a glass reaction vessel from which the air had beendisplaced with dry nitrogen was added 5 ml. of DCPD at 60 C. which wascooled to form a solid at 24 C. 0.05 g. of molybdenum oxytrichloridewere added and mixed with a stainless steel rod. No reaction wasobserved. After about 45 minutes, the composition was heated to 60 C.resulting in a gelled polymer in about 2 minutes. The polymer curedsatisfactory at l40 C. resulting in a product of somewhat lower hardnessthan example 1.

EXAMPLE V] In a glass reaction vessel from which the air had beendisplaced with dry nitrogen were added 1 ml. of norbornene and 4 ml. ofDCPD each at a temperature of 60 C. and 0.05 g. of molybdenumoxytrichloride. The temperature was raised to l40 C. for 3 hoursresulting in a dark brown resinous solid having a Shore C hardness of70.

The above procedure was repeated except that norbornene is replaced with0.05 ml. of bicycloheptadiene and that 4.5 ml. of DCPD was used. Thecured composition exhibited a Shore C" hardness of 60.

EXAMPLE Vll In a glass reaction vessel from which the air had beendisplaced with dry nitrogen were added 5 ml. of heptane at C. and 5 ml.of liquid DCPD at 60 and 0.05 g. of molybdenum oxytrichloride and themixture gently agitated by shaking. A

polymeric gelatinous precipitate was formed in about 7 minutes.

The procedure was repeated except that the molybdenum oxytrichloride isreplaced with molybdenum pentachloride. No polymer was observed evenafter 16 hours when the test was discontinued.

The procedure was repeated except that the reaction mixture was 8 ml. ofn-heptane and 2 ml. of DCPD; again when employing molybdenumoxytrichloride polymer formed within a few minutes, but no polymer wasobserved using molybdenum pentachloride after l6 hours.

EXAMPLE Vlll To illustrate the suitability of the compositions of theinvention for laminating applications the following experiment wasconducted.

In an inert atmosphere 6 ml. ofliquid DPCD at about 35 C. (which hadbeen dried to less than l00 p.p.m. of water with calcium hydride) wasmixed with 0.02 g. of molybdenum oxytrichloride and the mixture pouredinto a Petri dish containing two layers of dried glass cloth. After 3hours, without any additional heat being applied, the laminate had curedto a Barcol hardness of 10.

EXAMPLE lX To illustrate that the cured compositions according to theinvention exhibit advantageous low water absorptivity the followingexperiment was conducted.

A composition of 5 ml. of DCPD and 0.02 g. of molybdenum oxytrichloridewas cured 2 hours at to form a resinous coupon. The weighed coupon wasimmersed in distilled water at room temperature (about 23 C.) for aperiod of time which it was carefully dried on the surface with a papertissue and reweighed, after which the coupon was again totally immersedin water and reweighed at various time intervals as noted in thefollowing table.

For comparison the procedure was repeated with a commercially availablebisphenol A based epoxy resin having an oxirane equivalent weight ofI90, cured with 14.5 phr meta phenylene diamine 16 hours at 80 and 4hours at C. to form a coupon oflike dimension. As may be seen from datain the table, the cured composition according to the invention absorbedonly about 0.4 percent water after 76 days compared to 7 days for thecured epoxy resin.

TABLE Time Water ahsurptivity ofcured resins 1 Weight GainPolycycluolefin Epoxy Resin day ().l2

2 days 0.07

7 days 0.05 0.40

30 days 0.9l

40 days 0.26

76 days 0.39

We claim as our invention: 1. A heat-curable composition comprising: a.at least one polycycloolefin having a strained carbocyclic ring, and b.from about 0.0] to about 5 mole percent based on polycycloolefin of atleast one oxyhalide of molybdenum or tungsten containing at least threeatoms of halogen per molecule. 2. A composition as in claim 1 whereinthe oxyhalide is of molybdenum.

3. A composition as in claim 1 wherein the oxyhalide is molybdenumoxytrichloride.

4. A composition as in claim 1 wherein the oxyhalide contains three orfour atoms of halogen per atom of metal.

about 175 C. by contacting said polycycloolefin with a catalytic amountof a catalyst consisting essentially of at least one oxyhalide ofmolybdenum or tungsten containing at least three atoms of halogen permolecule.

10. A process as in claim 9 wherein the polycycloolefin and the liquiddiluent, if employed, contain less than parts per million by weight ofwater and other protonic agents.

I I l I t

2. A composition as in claim 1 wherein the oxyhalide is of molybdenum.3. A composition as in claim 1 wherein the oxyhalide is molybdenumoxytrichloride.
 4. A composition as in claim 1 wherein the oxyhalidecontainS three or four atoms of halogen per atom of metal.
 5. Acomposition as in claim 1 wherein the polycycloolefin contains afive-membered ring.
 6. A composition as in claim 5 wherein thepolycycloolefin is at least 50 mole percent dicyclopentadiene.
 7. Acomposition as in claim 1 wherein the amount of oxyhalide is from about0.02 to 1 mole percent.
 8. A cured composition according to claim
 1. 9.A process for the polymerization of at least one polycycloolefin at atemperature in the range from about 20* to about 175* C. by contactingsaid polycycloolefin with a catalytic amount of a catalyst consistingessentially of at least one oxyhalide of molybdenum or tungstencontaining at least three atoms of halogen per molecule.
 10. A processas in claim 9 wherein the polycycloolefin and the liquid diluent, ifemployed, contain less than 100 parts per million by weight of water andother protonic agents.